rc column design
DESCRIPTION
RC column designTRANSCRIPT
n 8:=
0.Initial data:
Choose C25/30
S500
XC1/S4
fck 25N
mm2
:=
fcd 16.67N
mm2
:=
fyd 435N
mm2
:=
Ecm 31GPa:=
a 6.8m 0.05m n⋅+ 7.2m=:=b a 1.2m− 0.025m n− 5.8 m=:=
Location :
ks 0.2g:=
1. Values of loadings
Loadings at column's base:
Fundamental series(GF):•Med1 180kN m⋅ 5kN m⋅ n⋅+ 220 kN m⋅⋅=:=
Med2 185kN m⋅ 10kN m⋅ n⋅+ 265 kN m⋅⋅=:=
Medf Med2 265 kN m⋅⋅=:=
Ned1 1670kN 5kN n⋅+ 1.71 103
× kN⋅=:=
Ned2 1900kN 10kN+ 1.91 103
× kN⋅=:=
Nedf Ned2 1.91 103
× kN⋅=:=
Seismic series(GS):•Med3 185kN m⋅ 10kN m⋅ n⋅+ 265 kN m⋅⋅=:=
Med4 200kN m⋅ 5kN m⋅ n⋅+ 240 kN m⋅⋅=:=
Meds Med3 265 kN m⋅⋅=:=
Ned3 1300kN 10kN n⋅+ 1.38 103
× kN⋅=:=
Ned4 1280kN 5kN n⋅+ 1.32 103
× kN⋅=:=
Neds Ned3 1.38 103
× kN⋅=:=
Vedmax 90kN 5kN n⋅+ 130 kN⋅=:=
Loadings of the cantilever(at 20cm from the column's side)
V1 180kN 2.5kN n⋅+ 200 kN⋅=:=H1 0.1 V1⋅ 20 kN⋅=:=
2.Dimensions
Column's length
l0.6− m 1.5m−( )−
2a+ 8.25 m=:=
Buckling length:
l0 2l 16.5 m=:=
Predesign of the column:
-technological condition: multiple of 5cm
-fire resistance condition:
for R120(120 min exposure until colapse),multiple sides exposure and µg=0.2 (tab.6.2-Kiss):
bc 20cm:=hc 20cm:=and the concrete cover a=4cm
-minimum dimension condition:
bc 30cm≥hc 30cm≥
-resistance condition:
for end column:
n1 1.6:=
n1Nedf
0.8 fcd⋅⋅ 2.292 10
3× cm
2⋅=
So min bc x hc = 2292 cm2
Choose
bc 50cm:=hc 50cm:=
bc hc⋅ 2.5 103
× cm2
⋅=
-normalised axial force condition:
for :
bc 50cm:=hc 50cm:=
vd
Neds
fcd bc⋅ hc⋅0.331=:=
vd 0.4≤
-flexibility condition:
λlim 70:=
So,we have an intermediary column with 50x50 cross-section.
3.Moment increase due additional eccentricity
Eccentricity ea 20mm:=
MEd.1 Med1 Ned1 ea⋅+ 254.2 kN m⋅⋅=:=
MEd.2 Med2 Ned2 ea⋅+ 303.2 kN m⋅⋅=:=
MEd.3 Med3 Ned3 ea⋅+ 292.6 kN m⋅⋅=:=
MEd.4 Med4 Ned4 ea⋅+ 266.4 kN m⋅⋅=:=
4.Moment increase due second order effects
Approximative reinforcement
Area of cross-section:
Acs bc hc⋅ 2.5 103
× cm2
⋅=:=
Approximative reinforcemet area:
p1.5
100Acs⋅ 37.5 cm
2⋅=:=
Choose 8Φ25 with area
As 39.28cm2
:=
number of bars
n 8:=diameter :
ϕ 25mm:=
concrete cover
XC1:
cmindur 15mm:=
cnom cmindur 10mm+ 25 mm⋅=:=
d1 cnomϕ
2+ 37.5 mm⋅=:=
take
d1 40mm:=
Nominal rigidity
Isn π ϕ
2⋅( )⋅
4d1
hc
2−
⋅ d1hc
2−
1.732 104−
× m4
⋅=:=
Ic bchc
3
12⋅ 5.208 10
3−× m
4=:=
ρAs
Acs0.016=:=
ρ 0.01≥
Ks 0:=
Eurocode 1992-1-1 3.1.4
h0 2Acs
2 bc hc+( )⋅ 0.25 m=:=
ϕef 2.8:=
Kc 0.3 1 0.5ϕef+( ) 0.72=:=
EcdEcm
1.225.833 GPa⋅=:=
Es 200GPa:= 3.2.7 (4)
Nominal rigidity:
EI Kc Ecd⋅ Ic⋅ Ks Es⋅ Is⋅+ 9.688 104
× kN m2
⋅⋅=:=
Moments amplification coefficient
c0 8:=
βπ( )
2
c0
1.234=:=
NB π2 EI
l02
⋅ 3.512 103
× kN⋅=:=
Med.1 MEd.1 1β
NB
Ned1
1−
+
⋅ 551.81 kN m⋅⋅=:=
Med.2 MEd.2 1β
NB
Ned2
1−
+
⋅ 749.199 kN m⋅⋅=:=
Med.3 MEd.3 1β
NB
Ned3
1−
+
⋅ 526.265 kN m⋅⋅=:=
Med.4 MEd.4 1β
NB
Ned4
1−
+
⋅ 464.322 kN m⋅⋅=:=
5.Dimensioning of the longitudinal reinf.
µMed.2
bc hc2
⋅ fcd⋅
0.36=:=
υNedf
bc hc⋅ fcd⋅0.458=:=
d1 d2=
d1
hc0.08=
Fig. 3.6 b) (Kiss)
ωtot 0.60:=
Astot ωtot bc⋅ hc⋅fcd
fyd
⋅ 57.483 cm2
⋅=:=
Because from the approximative design it resulted a smaller value,we will use these datas.
As 64.32cm2
:=
number of bars
n 8=diameter :
ϕ 32m:=
d1 40 mm⋅=
Verifiying the minimum distance between reinforcements:
dr
hc 2 d1⋅−( )3
140 mm⋅=:=
dr ϕ>
6.Dimensioning of transversal reinforcement
Ved Vedmax 130 kN⋅=:=
Capable shear force•
VRdc = CRd.c η1⋅ k 100ρl fck⋅( )1
3⋅
⋅ k1 σcp⋅+
bc⋅ d⋅
d hc d1− 0.46 m=:=
γc 1.5:=CRd.c
0.18
γc
0.12=:=
η1 1:= -for heavy concrete
k 1200mm
d+ 1.659=:= < 2.00
ρlAs
bc d⋅0.02797=:= < 0.02
σcp
Nedf
bc hc⋅7.64
N
mm2
⋅=:=
k1 0.15:=
fck
fck
N
mm2
25=:= σcp
σcp
N
mm2
7.64=:=
dd
mm460=:=
bcbc
mm500=:=
VRdc CRd.c η1⋅ k 100ρl fck⋅( )1
3⋅
⋅ k1 σcp⋅+
bc⋅ d⋅ 1⋅ N 452.252 kN⋅=:=
VRdc 452.252 kN⋅=
Minimum capable shear force:
VRdc.min = νmin k1 σcp⋅+( ) bc⋅ d⋅
νmin 0.035 k
3
2⋅ fck⋅ 0.374=:=
VRdc.min νmin k1 σcp⋅+( ) bc⋅ d⋅ N⋅ 349.62 kN⋅=:=
Ved 130 kN⋅= < VRdc.min 349.617 kN⋅= < VRdc 452.252 kN⋅=
trasversal reinforcement will be constructive
Choose transversal reinforcement diameter:
ϕw 10mm:=
2 stirrups=>4 shear branches
Asw 4π ϕw
2⋅
4
⋅ 314.16 mm2
⋅=:=
Distance between stirrups in the critical zones
ϕ 3.2 104
× mm⋅=
bc 500mm:=
scr.max min 6 ϕ⋅bc 2 d1⋅−
3, 125mm,
125 mm⋅=:=
take
scr.max 120mm:=
ρw.eff
Asw
bc scr.max⋅0.00524=:=
ρw.min 0.005:=
ρw.eff ρw.min≥
it's OK , the minimum percentage of reinforcement is exceeded
Length of the critical zone:
l 8.25 m=
lcr max 1.5bcl
6, 600mm,
1.375 m⋅=:=
take
lcr 1.56m:=
Distance between stirrups in the non-critical zones
sncr.max min 20 ϕ⋅ min bc hc, ( ), 400mm, ( ) 400 mm⋅=:=
take
sncr.max 300mm:=
So:
-on the critical lengths=1.56m from the ground level Φ10/12
-under ground level,in the foundation zone, same Φ10/12
-in rest Φ10/30
7.Design of the short cantilever
distance from application point of the force to the connection point of the column
ac 20cm:=
Fed V1 200 kN⋅=:=
Hed H1 20 kN⋅=:=
bcant - cantilever thickness,taken as long as column thickness
Take :
bcant bc 500 mm⋅=:=
hcant 150mm:=
dcant 0.9hcant 135 mm⋅=:=
fcd 16.67N
mm2
⋅=
Longitudinal reinforcement:
M Fed ac⋅ Hed hcant⋅+ 43 kN m⋅⋅=:=
µM
bcant dcant2
⋅ fcd⋅
0.283=:=
ω 0.3412:=
Longitudinal reinforcement area will be maximum from the following two:
Asl ω bcant⋅ hcant⋅fcd
fyd
⋅ 9.807 cm2
⋅=:=
Approximative :
Asa0.15
100bcant⋅ hcant⋅ 1.125 cm
2⋅=:=
so
Asl 9.807 cm2
⋅=
take 4Φ18
Asl 10.16cm2
:=
Stirrups :
ac
hcant
1.333=
ac
hcant
0.5>
we will have horizontal stirrups and vertical stirrups
horizontal stirrups:•
Ash 0.25 Asl⋅ 2.54 cm2
⋅=:=
take 4Φ10
Ash 3.14cm2
:=
vertical stirrups:•
Asv 0.5 Asl⋅ 5.08 cm2
⋅=:=
take 5Φ12
Asv 5.65cm2
:=
distance between stirrups:•take
ds cmindur10
2mm+ 20 mm⋅=:=
ds 20mm:=
-distance between horizontal stirrups:
sh
hcant 2 ds⋅−( )3
36.667 mm⋅=:=
approx. 40mm
-distance between vertical stirrups:
take the length of the cantilever as:
lcant 300mm:=
( )
sv
lcant ds−( )4
70 mm⋅=:=
8.Column verification for manipulation
distance from both ends to the point where the column is rooted
x 0.2 l⋅ 1.65 m=:=
dead load:
gcol Acs 25⋅kN
m3
6.251
mkN⋅=:=
V1 gcoll
2⋅ 25.781 kN⋅=:=
Mr 8.62kN m⋅:=Mc 10.77kN m⋅:=
d 460mm:=z 0.9d 414 mm⋅=:=
µmMc
bc d2
⋅ fcd⋅
6.107 103−
×=:=
ωm 0.01:=
Asl.h ωm bc⋅ d⋅fcd
fyd
⋅ 0.881 cm2
⋅=:= Satisfied
Ved 130 kN⋅=
VRdc.min 349.617 kN⋅=
VRdc 452.252 kN⋅=
ctgθ 1VRdc.min Ved−( )
VRdc Ved−1.5⋅+ 2.022=:=
s1.h
Asw z⋅ fyd⋅ ctgθ⋅( )V1
4.438 m⋅=:= Satisfied
9. Checking column at assembling
(l-x)V1+gcol*x*x/2-gcol*(l-x)*(l-x)/2=0
l 8.25 m=
x 1.65 m=
gcol 6.251
mkN⋅=
V1 19.59kN:=
Mc 30.30kN m⋅:=
Mr 8.62kN m⋅:=
µmMc
bc d2
⋅ fcd⋅
0.017=:=
ωm 0.0171:=
Asl.h ωm bc⋅ d⋅fcd
fyd
⋅ 1.507 cm2
⋅=:= Satisfied
s1.h
Asw z⋅ fyd⋅ ctgθ⋅( )V1
5.84 m⋅=:= Satisfied
Mark Diameter Type Length(m) Quantity 8 10 18 32
1 32 S500 8,62 8 68,96
2 18 S500 1,50 4 6,00
3 10 S500 1,68 47 78,96
4 10 S500 1,17 47 54,99
5 10 S500 2,42 4 9,68
6 12 S500 1,14 5 5,7
9,68 139,65 6,00 68,96
0,39 0,62 2,00 6,31
3,82 86,06 11,98 435,15
Total 537,00
Total length(m)
Reinforcement extras
Length by diameter
Total weight(kg)
Weight for diameter(kg/m)